21022001001 has 6 divisors (see below), whose sum is σ = 30365112570. Its totient is φ = 14014667328.

The previous prime is 21022000903. The next prime is 21022001029. The reversal of 21022001001 is 10010022012.

It can be written as a sum of positive squares in only one way, i.e., 20473317225 + 548683776 = 143085^2 + 23424^2 .

It is not a de Polignac number, because 21022001001 - 2¹⁹ = 21021476713 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (9), and also a Moran number because the ratio is a prime number: 2335777889 = 21022001001 / (2 + 1 + 0 + 2 + 2 + 0 + 0 + 1 + 0 + 0 + 1).

It is not an unprimeable number, because it can be changed into a prime (21022001101) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1167888936 + ... + 1167888953.

It is an arithmetic number, because the mean of its divisors is an integer number (5060852095).

Almost surely, 2^21022001001 is an apocalyptic number.

It is an amenable number.

21022001001 is a deficient number, since it is larger than the sum of its proper divisors (9343111569).

21022001001 is a wasteful number, since it uses less digits than its factorization.

21022001001 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2335777895 (or 2335777892 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 9.

Adding to 21022001001 its reverse (10010022012), we get a palindrome (31032023013).

The spelling of 21022001001 in words is "twenty-one billion, twenty-two million, one thousand, one".